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1981 Mercury 40HP EL fuel issue

D

DMorphew

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I have a 1981 Mercury 400/40HP EL (red strio). I cleaned the carb, replaced needle seat, gaskets, o-rings, new filter, fuel line, rebuilt fuel pump. I will squeeze the bulb until it's very firm. I see gas in the float bowl and at bottom of carb. Nothing is coming up into the carb. I've inspected the carb five times for possible blockage, nothing found. Any help would be greatly appreciated.

What draws or pushes fuel up into the carb where the butterfly is located?
 
Sorry for the confusion, I have 1971 mercury 400 EL. I research the cab type, fuel flows through the carb via pressure. What creates the pressure to send fuel into the engine?
 
That is what I thought. Currently this is how the system works, prime bulb - fuel travels (installed clear hose) through fuel pump into filter ( bulb gets hard) - fuel then travels into float bowl raising float which applies pressure to the needle - needle is raised up shutting off fuel supply coming from fuel pump. Additional fuel enters once the float lowers causing needle to drop down. Fuel never makes it to the butterfly.
 
I sprayed fuel into carb, it wants to start. We have compression, something tells the gas lines to and from the fuel pump are connected wrong. I'm not able to locate any diagrams on this. Does anyone know where I might find this info?
 
something tells the gas lines to and from the fuel pump are connected wrong
Click to expand...
If this statement is true lines are correct...
fuel travels (installed clear hose) through fuel pump into filter ( bulb gets hard) - fuel then travels into float bowl raising float which applies pressure to the needle - needle is raised up shutting off fuel supply coming from fuel pump. Additional fuel enters once the float lowers causing needle to drop down.
Click to expand...
Fuel is drawn into engine from crankcase compression and atmospheric pressure.When piston is at TDC the crankcase forms a vacuum, then the outside atmospheric pressure(14+psi)rushes thru carb and is sped up passing thru venture, this causes a pressure drop in bowl and fuel is pulled up thru emulsion tube.(short version)
 
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Thanks fazebullet that does make sense. I was able to purchase a 1981 Mercury 40hp for 25.00 thus verifying gas lines were connected on wrong fuel pump ports. At this point I have fuel at the spark plugs (plugs are wet). motor fires but will not start. Carb is dripping fuel. Spraying fuel into carb changes nothing. Re-verified float and needle for proper adjustment, both are correct. Additional thoughts?
 
Compression tests indicates top cylinder has 130psi. bottom cylinder has 128psi. verified good spark at plug diode? (bottom end of plug) when holding plug wire away from plug no spark was identified. Not sure if this satisfactory.
 
Verified spark jump to be 1/2 inch.

Spark jump is 1/2 inch, compression is 130 psi (top cylinder) 128psi (bottom cylinder) carb has been rebuilt, fuel pump has been rebuilt, spark plugs are wet with fuel. (good, clear premium fuel) no ethanol crap. Squirting fuel directly into carb does nothing other than flood motor. What the heck am I missing?
 
How does one verify this? I have never performed this task on old Merc's. I will try to locate a manual explaining the procedure. If you know where I could find a manual that would be greatly appreciated. Thanks for everything up to this point.
 
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